Samsung also makes some very good plasma's and in fact might be better than panasonic in entry level plasma's. But with panasonic's new 2012 line even the mediocre UT has now been overhauled and sparkles amongst its other brothers. Would it be fair to compare ST50 with E550..............probably not. If you want to look into reviews:
Samsung PN51E550 Review, Plasma HDTV, 51", 3D Ready Smart TV
Panasonic TC-P50ST50 Review - 50" Plasma 1080p 3D, Infinite Black Pro, Viera Connect Smart TV
Panasonic TC-P50ST30 Review: Watch our Video Review Budget Price 3D Plasma, TCP50ST30
Suggest you to study all the reviews and then go and demo the tv's you have shortlisted, side by side if possible and then decide. Both are excellent tv's. Always trust your eyes..........play HD and SD and see how the tv handles the signals. Take your time and make a decision.
Samsung PN51E550 Review, Plasma HDTV, 51", 3D Ready Smart TV
Panasonic TC-P50ST50 Review - 50" Plasma 1080p 3D, Infinite Black Pro, Viera Connect Smart TV
Panasonic TC-P50ST30 Review: Watch our Video Review Budget Price 3D Plasma, TCP50ST30
Suggest you to study all the reviews and then go and demo the tv's you have shortlisted, side by side if possible and then decide. Both are excellent tv's. Always trust your eyes..........play HD and SD and see how the tv handles the signals. Take your time and make a decision.